Flue damper with latching means



Feb. 14, 195@ A. P. TERRY FLUE DAMPER WITH LATCHING MEANS Filed Feb. -21, 1949 m w w m Patented Feb. 14, 1950 UNITED STATES PATENT OFFICE FLUE DAMFEB WITH LATCHING MEANS Augustus, P. Terry, Berkeley, Calif. I Application February 21, 1949, Serial No. 77,475

This invention relates to and in general has for its object the provision of a latching mechanism for locking the damper of a flue in its closed position.

More specifically, the object of this invention resides in the provision of a fiue controlled by a damper pivoted therein for rotation on a horizontal axis and wherein the damper can be locked by means of a latch mounted on the fiue adjacent one of the free edges of the damper for limited travel along a fixed vertical axis and for rotation thereon in response to the movement of the damper.

The invention possesses other advantageous features, some of which, with the foregoing, will be set forth at length in the following description where those forms of the invention which have been selected for illustration in the drawings accompanying and forming a part of the present specification are outlined in full. In said drawings, three forms of the invention are shown, but it is to be understood that it is not limited to such forms, since the invention as set forth in the claims may be embodied in a plurality of forms.

Referring to the drawings:

v Fig. l is a vertical mid-section of a damper controlled fiue provided with a latching mechanism embodying the object of my invention.

Fig. 2 is an isometric view of the latching mechanism shown in Fig. 1 in side elevation.

Fig. 3 is a front elevation of the latching mechanism illustrated in Figs. 1 and 2.

Fig. 4 is an illustration of a blank from which the bracket and cam track of my latching mechanism can be formed.

Fig. 5 is a perspective view of a modified form e Claims. (61. 126285) of latching mechanism embodying'the object of my invention.

Fig. 6 is a perspective view of a still further modification of the latching mechanism shown in Figs. 1-5 inc.

All three modifications of the latching mechanism shown in the above figures are used in con- Junction with a flue I, in which istjournaled on a diameter thereof a horizontally extending shaft 2. Fixed to the shaft 2 is a damper 3 provided on its lower, right-hand end as shown in Fig. 1 with an eye 4 through which a cable, cord or chain 5 can be attached.

Riveted to the left-hand side of the flue l in a vertical plane containing that diameter of the flue which bisects the shaft 2 is a bracket generally designated by the reference numeral 6.

The bracket 6 includes opposed upper and lower 2 i inwardly extending arms I and 8 and a cam blank 9. Journaled in the outer ends of the upper and lower arms 1 and 8 is a latch stem H and formed in the cam blank 9 is a tortuous cam track generally designated by the reference numeral I2. The cam blank 9 is formed substantially into a cylinder surrounding the stem I! and extending diametrically through the latch stem Ii is a cam follower pin I3. The lower wall of the cam track l2 starting from its right-hand end as shown in Fig. 2, or from its left-hand end as shown in Fig. 4, includes a fall I4 terminating in a notch IS, a rise l6 terminating in a point or apex IT, a fall i8 terminating in a notch I9, and a rise 21 terminating in an apex 22. For all practical purposes the apex 22 merges with the fall I4 even though the free edge of the cam blank does not form a complete cylinder with its opposite end. Although in general the profile of the upper wall of the cam track i2 is complementary to the profile of its lower wall, it is to be particularly noted that the notch or apex [5a of the upper profile is slightly offset to the left as viewed in Fig. 4 with respect to the notch i5 of the lower profile. Similarly, the notch Ila of the upper profile is slightly offset to the right with respect to the apex ll of the lower profile and the apex l9a of the upper profile is slightly offset to the left with respect to the complementary notch iii of the lower profile. As will be presently more fully explained, this construction is essential to insure that the latch stem ll always rotates in a clockwise direction as viewed in Figs. 1, 2 and 3 in response to each upward and downward travel of the stem.

The lower end of the stem ll terminates in a point or teat 23 and mounted immediately above this teat 23 is a sector-shaped latch 24 subtending an angle of slightly less than Mounted on the left-hand side" of the damper 3 immediately adjacent the locus of the latch 24 is a spacin member 25 and formed integral with this spacing member is a catch or keeper 26 with which the latch 24 is arranged to engage when the latter assumes an inwardly directed position.

Assuming as shown in Fig. 1 that the damper is in its closed and latched position and that it is desired to open the damper, the right-hand end of the damper 3 is pulled downwardly by the cable 5, thereby causing the left-hand end thereof to rise and engage the teat 23 of the latch stem H. The latch stem moves upwardly under the influence of the upward movement of the damper. Momentarily, the follower pin [3 only moves vertically away from its seat in the notch IQ of the lower profile of the cam track without any rotary movement. However, upon its continued upward travel it engages th complementary rise of the upper profile immediately to the left of the point or apex I 9a thereof. The further upward travel of the stem I l is therefore accompanied by a clockwise rotation during that time that the follower pin is traveling in engagement with the rise of the profile immediately to the left of. the apex [9a. As a. result of thismovement the stem II turns through an angle of about 90. By this time the left-hand end of the damper is moving downwardly under the influence of gravity with the stem H following it, for a portion of the latch 21 still underlies the catch or keeper 26. During the downward travelof the stem II the follower pin 13 drops to thefall l4 and in sliding downwardly along the profile of this wall causes the stem ll through substantially another 90, thereby bringing the latch 2'! completely out of registration with the-keeper 26'sothat the damper 3 can rotatein counter-clockwise direction to its fully opened position. The damper is maintained in its open position due to the weight of the spacer 25.

In the open position of the damper, the right endof the follower pin as viewed in Figs. 2 and 3 rests in the notch it of the lower profile of the cam track. To close the damper and lock it in its closed position, the right-hand end-of the damper as viewed in Fig.- 1= is pulled downwardly so as to bring its left-hand end into engagement with the teat 28 of thelatch stem- 51. The latch stem H moves upwardly in response to' theupward movement of the left-hand end of the damper and momentarily rises only vertically without any rotary movement. When, however, the rightend ofthe follower pin I 3 engages the rise of the upper profile of the ca track immediately to the left of its apexl5w as viewed in Fig. 2, the further upward movement of the stem- H is accompanied by a clockwise rotary movement through an angle-of about-90. During this interval oftime, the pull on the cable 5 hasbeen' discontinued to thereby permit the'left hand end of the damper to start to fall, and with it thestem' H. Upon the downward move-- ment of the stem ll the follower pin 13 drops from the notch l lw of the upper profil to the fall M of the lower profile, whereupon. the further downward movement of the stem is ac companied by -a clockwise rotary movement of a further 90 angle. In this position of the stem H and the follower pin t3, the: latch 24 completely underlies the keeper 42d thereby looking thedamper 3 in: its closed position across the fluev l.

In recapitulation, each upward. movementv of the valve stem is accompanied by. a clockwise rotary movement thereofto the extent of. 90, and each downward movement. thereof. is likewise accompanied by a. clockwise rotary movement of 90; Since-the latch 24; subtends an angle of substantially 180, eachv complete cycle of movement of the latch stem. Mr, that is,;0ne upwardmovement and .one downward-movement, will causethe latch 24 to either assume a posi tion in complete registration with the-keeper 2B ora position completely out ofregistration therewith. As shown in dotted line in Fig. l, thefirst rotary movement. of the latch 2.4 from its fully closed. position. does not serve to bring it out of complete registration. with the keeper 25;, but only partially so.

to rotate It thesecond' rotary move- 75.

4 ment of the latch in response to the downward movement of the latch stem l l which serves fully to disengage or rotate th latch 24 out of registration with the keeper 26.

Although the cam track I2 includes two pairs of diametrically opposed hills and valleys, actually only one pair is required so long as the follower pin l3 extends outwardly from both sides of the latch stem II and so long as the cam blank only extends halfway around the latch stem II. It is onlywhen the follower pin l3 extends from only one side of the latch stem that both pairs of hills and valleys are required. The modification shown in Fig. 5 is generally similar to the structure above described with reference't'd Figs. 1 to 4 inclusive. Like the previousmodification, resort is had to a bracket generally designated by the reference numeral 31 arranged to be riveted or otherwise secured to the inner wall of the flue I in a vertical position. However, in this modification the cam track generally designated by the reference numeral 32 is formed integral with the latch stem 33 and rotates therewith. The profiles; of the upper and lower walls of the cam track-'32 are identical withtheprofilesof the cam track l2 of the modification. shown in Figs. 1- to 4 inclusive. Since the cam track is made-integral with the stem 33 and rotates therewith, thefollower pin 34 is mounted on the rear wall. 35 of the bracket 31 and is consequently stationary; In bothmodifications, however, there is of course a relative movement between the cam track and the follower pin. In. the first modification the cam track is stationary and the follower pin rotate's with the latch stem, whereas in. the latter modification the follower pin is stationary and the cam track rotates. Except forthis difference with respect to the cam track and the follower pin,. and thedetails of construction of the bracket 3! and the blank fromwhich. it is die-stamped; the two modifications. are identical and serve to rotate their. corresponding latches through 180, in response tov each upward and downward travel of the latch stem.

In the modification shown. in Fig 6,. resort is had to a bracket. generally designated by the reference numeral 4|. in which a latch stem. 42 is journaled for rotary movement therein-and also for limited vertical movement. The required rotary movement of the latch stem 42 is produced by a pair of longitudinally spaced cam pin followers; 43 and 44, carried by the latch stem 42 and arranged to travel along cam profiles 45- and: 4e formed on the upper and lower ends of a cam cylinder 41. The (Jam cylinder 41-, of course, circumscribes the latch stem AZ- and is rigidly mounted. on. the lower arm 4.8 01? the bracket 4|. Generally, the profile 4'5 is'comple mentary to the'profile 46, although as? in the case of the two modifications previously described, the notches of the profile 45 complementary to thepoint's orape-Xes of profile 46' are offset laterally so as to. insure the rotation of the latch stem 42 in the same direction (clock- Wise as shown in'thietwo previous modifications described).

I'claimr l. A device of the character described com".- prising: a flue; a damper pivoted to and within said flue for rotation on an horizontal axis; a bracket member secured to and within saidzfiue above the horizontal plane including, said axis and in the path of" rotation of said' dampe -t a latch stem member. iOumaIedin said bracketcn a vertical axis for rotation and limited longitudinal movement therein; a radially extending latch secured to the lower end of said stem member; a catch secured to the upper face of said damper in vertical alignment with said latch when said latch is directed inwardly of said flue; and cam track and cam follower means associated with said stem member for causing said stem member to rotate through substantially 180" in response to each cycle of upward and downward movement thereof.

2. A device of the character described comprising: a flue; a damper pivoted to and within said flue for rotation on an horizontal axis; a bracket member secured to and within said flue above the horizontal plane including said axis and in the path of rotation of said damper; a latch stem member journaled in said bracket on a vertical axis, said stem being arranged for limited longitudinal movement relative to said bracket; tortuous cam tracks circumscribing said latch stem member and fixed to one of said members; cam track follower means secured to the other of said members in operative association with said cam tracks; a sector-shaped latch secured to the lower end of said latch stem and extending radially therefrom; and a catch secured to said damper in vertical alignment with said latch when said latch is directed inwardly of said flue.

3. A device of the character described comprising: a flue; a damper pivoted within said flue for rotation on an horizontal axis; a bracket member mounted to and within said flue above the horizontal plane including said axis and in the path of rotation of said damper; a stem member mounted in said bracket member for rotation and vertical sliding movement therein; a tortuous cam track circumscribing said stem member and secured to one of said members; a cam follower pin secured to the other of the members with a portion thereof disposed within the confines of said tortuous cam track; a sectorshaped latch fixed to the lower end of said stem member radially thereof for rotation and vertical movement therewith; and a catch fixed to the upper face of said damper in vertical alignment with said latch when said latch is directed inwardly towards the center of said flue.

4. A device of the character described comprising: a flue; a damper pivoted to and within said flue for rotation on an horizontal axis; a bracket member secured to and within said flue above the horizontal plane including said axis and in the path of rotation of said damper; a latch stem member journaled in said bracket on a vertical axis for rotation and limited longitudinal movement therein; a radially extending latch secured to the lower end of said stem member; a catch secured to the upper face of said damper in vertical alignment with said latch when said latch is directed inwardly of said flue; and a vertically tortuous cam track surrounding said stem member and secured to said bracket members; and a cam follower disposed in said cam track and secured to said stem member, said cam track including a pair of opposed hills and valleys of such contour that said stem is caused to rotate substantially in response to the up and down movement of said cam follower in one pair of the adjacent hills and valleys of said cam track.

5. A device of the character described comprising: a flue; a damper pivoted to and within said flue for rotation on an horizontal axis; a bracket member secured to and within said flue above the horizontal plane including said axis and in the path of rotation of said damper; a latch stem member journaled in said bracket on a vertical axis for rotation and limited longitudinal movement therein; a radially extending latch secured to the lower end of said stem member; a catch secured to the upper face of said damper in vertical alignment with said latch when said latch is directed inwardly of said flue; opposed and complementary cam tracks fixed to said bracket member about said stem member, each of said cam tracks being provided with two pairs of contiguous hills and valleys; and a pair of cam track follower pins extending diametrically through said stem member with the ends thereof in sliding contact with said cam tracks.

6. A device of the character described comprising: a flue; a damper pivoted to and within said flue for rotation on an horizontal axis; a bracket member secured to and within said flue above the horizontal plane including said axis and in the path of rotation of said damper; a latch stem member journaled in said bracket on a vertical axis for rotation and limited longitudinal movement therein; a radially extending latch secured to the lower end of said stem member; a catch secured to the upper face of said damper in vertical alignment with said latch when said latch is directed inwardly of said flue; a cam track secured to and surrounding said stem member, said cam track including two pair of contiguous hills and valleys; and a follower pin mounted on said bracket with its free end disposedv in said cam track.

AUGUSTUS P. TERRY.

REFERENCES CITED The following references are of record in the flle of this patent:

UNITED STATES PATENTS Number Name Date 1,785,385 Lauer Dec. 16, 1930 

